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A117959 Perrin numbers which are divisible by their digital root. 1
2, 3, 5, 7, 10, 12, 39, 90, 486, 1130, 1497, 1983, 3480, 4610, 10717, 24914, 33004, 57918, 76725, 134643, 178364, 549289, 727653, 1691588, 2240877, 2968530, 3932465, 5209407, 12110402, 28153269, 65448410, 86700684, 114853953, 1089264462, 1911525877, 3354494070 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
1130 is in the sequence because (1) it is a Perrin number, (2) the digital root is 5 and (3) 1130 is divisible by 5.
MAPLE
R:= NULL: count:= 0:
a:= 3: b:= 0: c:= 2:
while count < 100 do
q:= a+b;
a:= b; b:= c; c:= q;
dr:= c mod 9; if dr = 0 then dr:= 9 fi;
if c mod dr = 0 then R:= R, c; count:= count+1;
fi
od:
sort(convert({R}, list)); # Robert Israel, Mar 16 2023
MATHEMATICA
Select[Union @ LinearRecurrence[{0, 1, 1}, {2, 3, 2}, 100], Divisible[#, Mod[# - 1, 9] + 1] &] (* Amiram Eldar, Feb 06 2021 *)
CROSSREFS
Intersection of A001608 and A064807.
Cf. A010888.
Sequence in context: A002822 A191327 A109598 * A117952 A090420 A162999
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), May 03 2006
EXTENSIONS
Data corrected by Amiram Eldar, Feb 06 2021
STATUS
approved

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Last modified February 23 04:31 EST 2024. Contains 370267 sequences. (Running on oeis4.)